Mono, or something else? Depression and fatigue.

17 year old male here. Over a year ago I was diagnosed mono, but I never had any swelling or pain in my throat/neck nor any infection. This is making me ponder the question if I might've had something else with similar symptoms? Only a blood test that showed that I had had mono was there to prove it, nothing while I had it and nothing other than that after I had it. I did also spend a week previously to that in a hospital bed while they took close to fifty bloodtests, took pictures of my liver (which was swollen but later shrunk down to regular size a year after), and put a camera down my throat and up my rectum.
The reason why I'm wondering this is that while not as severe as before, I am now still, over a year after I had it, depressed and fatigued. This is having bad results on both my studies and my social life. Being here obviously shows I am hesitant to go to a doctor, so any suggestions would be appreciated.
Might be related to my diabetes mellitus 1 diagnose.

I think you should go to a doctor, but that being said, it could still be the mono. I was diagnosed a year ago and I still have fatigue and muscle weakness. That seems fairly common -- and I have another friend who is past the one year mark, but is still tired.